The Open Championship at Royal Troon is expected to attract around 170,000 golf fans this week, according to estimates from tourism body VisitScotland, down 67,000 on last year's Open at St Andrews.

VisitScotland estimates the The Open at St Andrews last year delivered an economic impact of £140 million to Scotland, with almost two-thirds of spectators having attended from outside Scotland and 28 per cent from overseas.

Last year 237,024 people attended 144th Open Championship, which was extended into Monday due to weather delays, with spectator numbers having peaked on the Sunday at just over 45,000, according to official R&A figures.

The 2014 Open at Royal Liverpool Golf Club in Merseyside drew in 202,917 spectators.

VisitScotland said a total of 176,000 people attended The Open the last time it was held at Royal Troon in 1997.

The lowest Open Championship spectator figure recorded in the past decade was 123,000 at Turnberry for the 2009 competition.

VisitScotland said different venues attract different spectator numbers and St Andrews always attracts the biggest crowds of any Open venue.

The Open, the world's oldest professional golf tournament, is one of nine golf events being hosted in Scotland this year.

VisitScotland chief executive, Malcolm Roughead, said: “Golf is a vital part of the visitor economy with the ripple effect felt in shops, hotels, restaurants and a wide variety of other businesses across Scotland.

“These high-profile events don't just provide entertainment - they represent a multi-million pound benefit to Scotland, both urban and rural.

“Scotland continues to be the envy of world golf when it comes to the hosting of the biggest and best events in the game.

“In 2014, Scotland was showcased on the world stage with the hosting of the 'best-ever' Ryder Cup, and last year we followed that up with the return of The Open in St Andrews, the most successful golf event ever held in the UK and Ireland.

“The Open at Royal Troon and the eight other golf events in Scotland this year only enhance further our country's reputation as the home of golf, with many more lined up for future years such as the Solheim Cup in 2019.”